Drying machine for metal parts



Dec. 27, 1960 w. H. JACKSON DRYING MACHINE FOR METAL PARTS Filed Dec. 12, 1956 3 Sheets-Sheet 1 Dec. 2 7, 1960 W. H. JACKSON DRYING MACHINE FOR METAL PARTS 5 Sheets-Sheet 2 Filed Dec. 12, 1956 m ll l l l l H I I" H H INVENTOR. Mi z' w? /9, 7201 United States Patent DRYING MACHINE FOR METAL PARTS William H. Jackson, Birmingham, Mich., assignor to The Udylite Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 12, 1956, Ser. No. 627,803

8 Claims. (Cl. 34-225) This invention relates to improved drying apparatus, and more particularly to improved apparatus for drying relatively small parts in bulk.

The practice of the invention is particularly advantageous in connection with chute-type driers, and will be described herein in connection with a drying machine of this type. In its broader aspects it is also advantageous for use in drying apparatus of other types such as, for example, centrifugal driers, as will be appreciated by those skilled in the art. Chute-type driers are particularly well adapted for continuous drying in progressive steps, and are greatly to be preferred over certain ether types of driers, such as barrel type driers for drying certain small parts, since they subject the parts to a minimum tumbling action and can safely handle articles having. relatively soft coatings that may be damaged by excessive tumbling and abrasion. Chute-type driers are particularly advantageous when drying articles having dichromate coatings which, before being dried, are relatively soft and gelatinous and relatively easily damaged, especially at the corners and sharp edges of the parts to be dried.

It has heretofore been relatively difficult to provide a chute-type dryer having adequate work-handling capacity and drying speed for many commercial requirements. Driers of this type generally comprise a series of troughlike work-holding baskets, each one of which is pivoted and may be swung upwardly to discharge its contents into the next succeeding basket, or in the case of the last basket of the series, into a delivery receptacle. Warmed air is directed upon workpieces held in the baskets to dry them, and in previous driers this air is fed from nozzles located above the baskets. In order to provide adequate clearance for swinging the baskets to transfer the workpieces from one basket to the next, these nozzles must be spaced so far above the baskets that air directed through them is diffused and loses much of its velocity before striking the workpieces, anddoes not readily penetrate deeply into the massof the workpieces for efiicient and uniform drying.

Accordingly, one object of the present invention is. to improve drying apparatus of the forced air circulation type.

Another object is to provide improved drying apparatus in which a drying air stream is directed into a workpiece container, or basket through a side or bottom wall thereof and into intimate contact with a large portion of a mass of articles held therein.

These and other objects are accomplished by the present invention according to which drying air in forced air circulation type drying apparatus is directed into a workpiece receptacle, or basket through a perforate side or bottom wall thereof, and is thus brought into intimate contact with a mass of workpieces held in the basket. One illustrative embodiment of the invention comprises a chute-type drier including an elongated, trough-shaped, workpiece-holding basket having foraminous walls, such as perforated sheet metal, and means for directing a stream of air into the basket through such foraminous walls. The apparatus includes conduit means to direct the air into the basket where it con tacts and flows through a mass of workpieces held in the basket for eflicient and uniform drying.

The invention will be described in greater detail in connection with the accompanying drawings of which:

Figure 1 is a side elevational view of a drying apparatus embodying the present invention;

Fig. 2 is an end elevational view of the drying apparatus shown in Fig. 1;

Fig. 3 is a cross-sectional view of a portion of the" apparatus shown in Fig. 1, taken along the section line 33 thereof; and

Fig. 4 is a cross-sectional view of the apparatus shown in Fig. 3, taken along the section line 4--4 thereof.

Referring now to the drawing, a drying machine according to a preferred embodiment of the invention includes one or more chute-type drying baskets, two such baskets 10 and 12 being illustratively shown in Fig. 1,- arranged for simultaneous drying andprogressive trans fer. The construction of the work-supporting portions of the baskets 10 and 12 and their manner ofsupport within the housing 14 may be conventional. The baskets 10 and 12 are supported within a housing 14, which may be made of sheet metal panels 16 supported upon lon gitudinal, transverse, and vertical frame members 18, 20' and 22, respectiv'ely,;all securely fastened together as by welding or riveting to form a rigid housing structure. The lower portion of the housing 14, i.e., the portion withinwhich the baskets 10 and 12 normally rest, ispreferably of tank-like construction to receive moisture that may drain from workpieces held in the baskets. A drain outlet 25 isprovided in the fioor- 27 of the housing to facilitate disposal of accumulated moisture, and the floor 27 is appropriately sloped to direct drairi' moisture into the outlet 25. The entire housing 14 may, if desired, be supported above the floor upon a pair of' I-beams 23; A loading opening 17 is provided at the front of the housing 14, to the left as viewed-in Fig. 1, and a discharge opening 19 is'pro'vided at the rear. 1

T he. two baskets 10 and 12 are pivotallysupported ad jacent to each otherwithin the housing 14 upon sepa rate, transversely extending torque rods,-0r shafts 24 and 26, respectively, which are jour-nalled" in bearings 2 fixedto the transverse frame members ztls Each-Ba er 10-and l2 is normally supported in a horizontal position, and is swingable to: an upright, vertical position" (as shown in phantom-in Fig. 1') to discharg'eiitgc rite As shown, the baskets are actuatable by' jseparatef' 'h draulic cylinder assemblies 28 and 30 moimtd extrio ly of the housing and connected toarrfis 36'; a rigfdly 'afiixcd to the baskets along the upper sides th of, and project through slots- 38 and- 40 in wall of the housing 14. The hydraulic cylinders' 2'8 a'rrd 301 may be controlled individually by sepa valves'3z and 34; respectively, which maybe 'd through inlets 42 and- 44 m any convenient siaur'ce' of hydraulic'fluid under"pressure.-

A'sbest shown in-Figs. 3 and 4, each of the baskets '0 and 1'2 may comprise a load bearingmajor wall portion formedof aperforated'rnetalsheet 46, the apertures 7 of which are relatively widely spaced and suflicieiitl'y smallto retain workpieces. placed in the baskti one portion.49 of the side wall of theb'asket is formedo'f a metal mesh having relatively closely spaced apertures 51. This mesh portion 49 extends' along substantially the-en: tire-length of the basket along the upp'er forwardsid'e thereof. It does not'support a large proportion of thc weight" of workpieces placed-in the basket and; therefdre, itineednnot be'asstrong: as the major wall portion- 46:

Accordingly its apertures 51 may be closely spaced to facilitate the passage of air through it. The wall portions 46 and 49 are firmly secured to and supported by a plurality of spaced angle iron members 48, 50 and 52 which are shaped to conform to the desired trough-like contour of the basket. The ends of the baskets and 12 are enclosed by fiat, perforated members 53 which may be formed of the same material as the member 46. The members 46 are extended beyond the rims of the baskets on the delivery sides thereof to form unloading chute surfaces 54. Upstanding, unloading chute side walls 56 are provided extending above the upper edges 58 of the baskets so that articles being discharged from a basket when it is tilted upwardly are confined to the unloading chute surface 54 and are caused to spill rearwardly into the basket disposed immediately beyond the basket being raised, or in case of the last basket 12 into a delivery receptacle 65.

Around its upper periphery, each of the baskets 10 and 12 is reinforced with angle iron frame members 60, flanges 63 of which extend outwardly to engage supporting members 61 mounted along the inner walls of the housing 14 to support the baskets 10 and 12 when they are lowered into their horizontal positions. The baskets 10 and 12 may also include inlet lips 62 extending inwardly from their forward edges to direct the flow of workpieces being charged into the baskets toward the center thereof, and to prevent undue piling up of the workpieces near the forward portion of the baskets. These lips 62 are preferably reinforced from beneath by an inwardly projecting sheet metal member 64, which also functions as an air bafiie to direct the flow of drying air.

The baskets are spaced from the shafts 24 and 26, being supported upon pairs of arms 66 and 68, which are fixed to the shafts 24 and 26, respectively, and extend radially therefrom. The arms 66 and 68 are securely welded, or otherwise fastened to the angle iron members 60 along the sides of the baskets, and are disposed one at each side of each basket. The shafts 24 and 26 transmit sufficient torque from one side of the baskets to the other side so that the baskets may be swung upwardly by a force applied only at one side of the machine, in this case through the projecting arms 36. When the hydraulic cylinders 28 and 30 are actuated to raise the baskets, force is transmitted through the shafts 24 and 26 to the opposite sides of the baskets, and the baskets are lifted evenly and smoothly to discharge their contents.

The baskets 10 and 12 are arranged in sequence with the discharge chute 54 of one basket arranged to fall generally into alignment with the inlet lip 62 of the next succeeding basket in the series when the one basket is raised to its vertical position. Although only two baskets are illustrated in the drawing, the drying machine may include as many baskets as desired, or as required for the job at hand. The last basket of the series, such as the basket 12, illustrated, is arranged to discharge its contents out of the housing 14 into any convenient receptacle such as a transfer cart 65, which may be placed at the end of the housing.

According to the present embodiment of the invention, each of the baskets 10 and 12 includes an external pocket 72 formed by an exteriorly mounted sheet metal member 70 spaced from and extending along substantially the full length of the forward portion of the basket, generally parallel to the Wall member 49. The member 70 is turned inwardly at its lower end and securely fastened to the wall member 46, and forms an external pocket 72 having an open top along its entire length and an interiorly facing apertured wall formed by the member 49. In operation of the machine, warm air forced into this pocket 72 escapes through the wall member 49 into a mass of workpieces held in the basket and circulates among the workpieces for rapid and efficient drying.

Drying air may be supplied by a rotary-type blower 74 mounted on top of the housing 14 and driven by any con:

venient source of power such as the electric motor 76, illustrated. The air passes from the blower through a conduit into a heating unit 82 which may be, for example, an indirectly heated, gas fired unit of conventional construction, and thence through a vertical inlet conduit 84 down along and outside of the housing 14 to the bottom thereof. The vertical inlet conduit communicates with a horizontal conduit 86 which extends beneath the baskets 10 and 12 along the length of the housing 14. Air is conducted upwardly from the conduit 86 and is directed into the pockets 72 of the baskets 10 and 12 by means of nozzle assemblies 88, which may be supported by brackets 90 secured to the housing, and which terminate in orifices 92 positioned immediately adjacent to and extending along the length of the open tops of the pockets 72. Air compressed by the blower 74 is first heated in the heater unit 82 and then conducted down beneath the baskets 10 and 12 and upwardly into the pockets 72, from whence it passes through the mesh walls 49 of the baskets and into the baskets to mix intimately with material held in the baskets and to dry such material.

In operation, the blower 74 and the heater unit 82 are both operated continuously, and a load of workpieces (not shown) is delivered through the inlet opening 17 into the first basket 10 and permitted to drain and to be dried by the passage of air through the workpieces for a predetermined length of time, the duration of which will depend upon the volume of work to be handled by the drying machine. After the elapse of the predetermined time, the first basket 10 is swung upwardly by actuation of the cylinder 28 to transfer the first load of workpieces from the first basket 10 into the second basket 12. The first basket 10 is then lowered into its horizontal position and a second load of workpieces is delivered into it. After the end of a second predetermined time period, the second basket 12 is swung upwardly to discharge its contents, either out of the machine, or into a. third basket if the machine includes more than two baskets. The second basket is then lowered to its horizontal position and the first basket is swung upwardly to discharge its contents into the second basket. Thus, the workpieces progress stepwise along the length of the machine from its input end to its output end.

Drying air in apparatus according to the invention is not merely directed upon the exposed, upper surface of a mass of workpieces supported in a basket, but is directed through a perforate wall of the basket and so forced to circulate throughout the mass for efficient and uniform drying of all the workpieces. Moreover, full control of the air stream is provided since the nozzle orifices 92 may be placed close to the baskets, and the drying air is confined (in the embodiment described by the nozzles 88 and the pockets 72) until it actually comes into contact with the workpieces. Substantially none of the drying air is lost by diffusion.

Additionally, in apparatus according to the invention, air inlet nozzles, and the conduits that feed them are disposed completely out of the way, and do not obstruct access to the baskets. In previous centrifugal type driers, for example, air is generally introduced from above the baskets through overhead nozzles, which obstruct access to the baskets, and which must be swung aside to permit loading and unloading of the workpieces, and then replaced for drying operation. According to the invention, on the other hand, drying air is introduced through side or bottom walls of the baskets. The air directing nozzles approach the baskets from below, or from the side, and do not obstruct access thereto.

In order to conserve heat and to increase the economy of operation of the machine, a portion of the air introduced into the housing 14 through the conduits 84 and 86 may be recirculated. Toward this end, there is provided an additional vertical conduit 94 leading from an outlet port 96 in the side wall of the housing 14 up to the inlet port (not separately designated) of the blower 74. Any convenient adjustable baffle or valving arrangement may be provided to control the proportion of air drawn from the housing 14 into the intake of the blower 74 and the proportion of fresh air drawn from the ambient atmosphere. In commercial practice recirculation of about 50% of the drying air has been found to provide optimum results, reducing heating costs without appreciably affecting drying speed.

There has thus been described improved drying apparatus of the forced air circulation type including means to direct a flow of drying air into a workpiece receptacle through a perforated wall thereof for efiicient and uniform drying of workpieces held in the receptacle.

What is claimed is:

1. Chute basket-type drying apparatus comprising a workpiece-holding basket having a perforate wall, a substantially imperforate sheet member attached to said wall exteriorly with respect to said basket and forming in conjunction with said Wall a pocket having an open side, means to support said basket in a position to hold a plurality of workpieces to be dried, an air conduit disposed below said basket, an air nozzle communicating with said conduit and extending therefrom toward said open side of said pocket, said air nozzle terminating in an orifice disposed adjacent to said open side when said basket is supported in said position and being adapted to direct air from said conduit into said pocket, and means to cause air to flow through said conduit, said nozzle, said pocket, and said perforate wall into a mass of workpieces held in said basket.

2. Drying apparatus comprising a workpiece holding receptacle having perforated side and bottom wall portions, means mounted on the outside surface of said perforate side wall portion for receiving air, said means comprising an imperforate lower member spaced from and extending along said side wall and the lower edge surface thereof being attached to said side wall portion thus de-. fining a longitudinally extending pocket open at its upper end, an outwardly projecting longitudinally extending flange member attached to said side wall portion and spaced from the upper edge surface of said lower member and defining therewith an air receiving aperture for said pocket, and said flange having a portion extending inwardly and downwardly from the inner surface of said side wall portion.

3. Drying apparatus comprising in combination a trough-like workpiece holding basket having a perforate side wall portion and a perforate load-bearing wall portion, said basket being movable between a drying and a load-unload position, air conduit means having one end portion thereof connected to air supply means and a central portion disposed beneath said basket and terminating at its opposite end in an air supply duct located adjacent to said side wall portion of said basket when said basket is in its drying position, and means on said side wall portion positioned to receive air from said supply duct and direct said air through said side wall portion and in a direction toward the bottom of said basket. 1

4. Drying apparatus comprising in combination a plurality of sequentially arranged trough-like workpiece holding baskets, each having a perforate side wall portion and a perforate load-bearing wall portion, each of said baskets being movable between a drying and a loadunload position, each said basket having associated therewith air supply conduit means, a central portion of said conduit means disposed beneath each said basket and an 6 opposite end portion terminating in an air supply duct located adjacent to said side Wall portion of said basket when said basket is in its drying position, means on each said basket on the said side wall portion thereof positioned so as to receive air from said supply ducts and direct said air through each said side wall portion and in a direction toward the bottom of each said basket.

5. Drying apparatus in accordance with claim 4 and including means to cause air to flow through said supply duct, said air receiving means and said perforate side wall.

6. A workpiece-holding basket for a drying machine or the like comprising a trough-like member having a perforate side wall portion and a perforate load-bearing Wall portion, means mounted on the outside surface of said perforate side wall portion for receiving air, said means comprising an imperforate lower member spaced from and extending along said side wall, the lower edge surface of said lower member being attached to said side wall thus defining a longitudinally extending pocket open at its upper end, an outwardly projecting longitudinally extending flange member attached to said side Wall portion spaced from the upper edge surface of said lower member and defining therewith an air receiving aperture for said pocket, and said flange having a portion extending inwardly and downwardly from the inner surface of said side wall portion.

7. Chute-type drying apparatus in accordance with claim 6 including means to circulate air from an external source through said air receiving aperture, said pocket and in a direction toward the bottom of said basket.

8. Drying apparatus comprising in combination a trough-like workpiece holding basket having a perforate side wall portion and a perforate load-bearing wall portion, said basket being movable between a drying and a load-unload position, air circulation means having a discharge side and a suction side, first air conduit means having one end portion thereof connected to the said discharge side of said air circulation means and a central portion disposed beneath said basket and terminating at its opposite end in an air supply duct located adjacent to said side wall portion of said basket when said basket is in its drying position, means on said side wall portion positioned to receive air from said supply duct and direct said air through said side wall portion and in a direction toward the bottom of said basket, and second air conduit means having one end located adjacent to said perforate load bearing wall portion and the other end connected to the said suction side of said air circulation means whereby a portion of said air is returned to said air supply means after passing through said basket.

References Cited in the file of this patent UNITED STATES PATENTS Re. 6,144 Burns Nov. 24, 1874 272,714 Leonard Feb. 20, 1883 1,470,242 Overton Oct. 9, 1923 1,925,210 Smith Sept. 5, 1933 1,973,347 Kelly Sept. 11, 1934 2,060,065 Gill et a1 Nov. 10, 1936 2,561,517 Ladge July 24, 1951 FOREIGN PATENTS 259,713 Italy Aug. 2, 1928 

